| Year | 1939 |
| Date | 11-May |
| Volume | 80 |
| Issue | 1,983 |
| Page | 549 |
| Category | Electrical |
| Part | 2 |
| Title | Magnetic Fields |
| Author | H.Chapman-Pincher |
| Notes | How magnetism is used to produce both alternating and direct current. Wire cutting lines of magnetic force, generation of alternating current, improved genrator, commutator for production of direct current |